Method and apparatus for drawing sheet glass



'@Q wd-0. 27, 1931. E. T. FERNGREN METHOD AND APPARATUS FOR DRAWINGSHEET GLASS Original Filed Oct. l2. 1922 3 Sheets-Sheet l Oct. 27, 1931.E. T. FERNGREN METHOD AND APPARATUS FORDRAWING SHEET GLASS OriginalFiled Oct.

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METHOD AND APPARATUS FOR DRAWING SHEET GLASS QQCN /57/8/7. www@ 77Z7/VEY Patented Oct. 27, 1931 UNITED s'rA'ras rTl-:N'r OFFICE ENOCH T.FEBNGBEN, F TOLEDO, OHIO, BBIGNOB TO LBBEY-WENB-FOBD GLASS 00H- PANY,0F'. TOLEDO, 0R10, .L CORPORATION OF OHIO nmol) AND APPABATUB'JOBDRAWING SHEET GLASS Application October 18, 1928, lex-k1 No. 593,988.Renewed lay 14, 1830.

This invention'relates to the art of drawing sheet lass, and morearticularly to a methot and a paratus or drawing sheet glass downwa lyfrom the source of sup ly.

' One ofthe principal diiliculties hereto ore encountered in drawinsheet glass downward has been to provide a freely flowing source ofmolten glass, and at the same time so support and sus nd this sheetsource that there would be equate resistance to the drawing stress, sothat the sheet would not run away under the infiuence of gravi It isalso diiiicult to eliminate surface mar ings and lines of strain onanysheet drawn downwardly throu tendency of the coo plastic glass to adhereto the edges of the orifice from which it flows.

- The apparatus here disclosed aims to overcome these obstacles by owingthe molten 2o glass downwardly around and through a partially hollowanchoring tile or simllar supporting member positioned in the orifice orslot. This member is so rforated or honey-l combed with passages t at alarge surface area is presented to which the ilowing glass may adhere.This resistance will be imparted, in the main, to that glass which flowsto the interior of the sheet source, so that the glass iowing down theoutsde'of the supporting member 'may be kept relatively hot and in ahigher degree of fluidity so that the tendency to adhere to the walls ofthe recep tacle will be greatly decreased andsurface markingspractically eliminated. The apparatus further embodies a preferred formof receptacle for delivering the molten glass to the drawing orice in aproper state o f plasticity, and also a preferred form of yieldingsupport for the anchoring member or members so that the drawing stressesin the sheet source may be made more or less self-compensating andconstant.

The invention will be more clearly understood and further objects andadvantages will become apparent from the following detailed descriptionof two forms of apparatus adapted to carry out the principles of thisinvention.

In the accompanying drawings;

Fig. 1 is a perspective, partly in vertical an orifice, due to thesection, through one form of the apparatus.

Fig. 2 is a transverse vertioa section throu h the receptacle, showingthe anchor-4 y ing ti e in side elevation. The outline of the Howingglass is indicated in broken lines. f

Fig. 3 is a transverse vertical section through the anchoring member.Figi is an end elevation of the anchoring mem r. l

Fig. 5 is a longitudinal vertical section through a diierentmodification, embodying apre erred form of adjustable supportingoranchoring means. 6 is an. end elevation showing the yiel able andadjustable supports 'for the a5 prm of anchoring member disclosed in 1 vig. 7 is a side elevation of this anchoring or supportin member, one ofthe partsv thereof being bro en away to facilitate the disclobsure.

ig. 8 is a pers tive i ustratin the de sign of the receicle fordeliveiing the molten glass to the draw-point. A

l Referring first to the form of the invention shown iny Figs. 1 to 4inclusive, 1 indicates a portion of the shal owl rece tacle for themolten glass 2 which is delivered thereto from any suitable source ofsuppl such as a continuous tank furnace. At 3 t e bottom walls of thereceptacle 1 slope downwardly to the transverse slot or orifice 4,forming a sort of outlet funnel for the molten glass.

Within this slot or passage 4, is'positioned the anchoring tile orsupporting member 5 sa which may be given a variety of forms, its Yfunction being to act as a 'de and supporting means for the molten glasswhich' ows down to form the sheet source. Asv here illustrated, thismember consists of a pair of upper parallel side members 6 and a thirdcentral member 7 positioned parallel to but below the members 6. Thethree members 6 and 7 are joined at intervals by a series ofcross-braces or partitions 8 and 9, which serve to hold the side membersin spaced relation and at the same time rovide a series of interiorpassages l() and 11 t rough i which the molten glass may How. The en-ltire tile may be supported in any suitable 10tsol ` of lass forming thesource of manner, and as shown is carried at its ends by supportin arms12 restin on led es 13 at the ends o ythe slot or ori ce. Eac sidemember 6 of the anchoring tile 5 is provided adjacent its lower end withan outwardl extending ridge or shelf 6', each of whic provides a meansforaccumulating a supply of molten glass and temporarily supporting thesame on the outer side of t e tile member before it `ilows around theinwardly curving lower ends of the members 6 to merge with the glassiowing through the interior pass 10 to form the sheet splurce at thelower edg'eof the anchoring t e i It will .be noted that the supportingtile is positioned so that its upper face 13' is belowv the normallevelof the molten glass 2, within the receptacle 1, and the lower edge 14 ofthe central member 7 is positioned considerably below the slot ororilice 4. The molten glass which is delivered tothe outlet passa e 4 ina fairly hot and fluid condition will ow down through the interior pa v10 and 11 in the supporting tile and will a so flow 'in thin streamsaround the exterior thereof as indicated at 15 and 16. The lass flowingthrough the interior pass es o the supporting tile will become somew atcooled and will tend to adhere to the comparatively large Aarea of tilesurface to which it is exv posed, thus developing a sufn'cientresistance to the down flow of the lass to overcome the influence ofgravity an sus end the mass eet 17 whichl is ing drawn away from thelower edge of thisglass mass.

The molten glass flowing around the exterior of the supporting tile asat 15 and 16 is maintained 1n a more hi hly heated an fluid condition sothat it wi iiow freely and not tend to adhere to the draw-off lips 18 atthe sides of the slot or orifice; To main. tain the proper heatedconditionv of this ex# terior flow of glass, heat is directed -fromchambers 19 a inst the two sides ofthe flowing glass a jacent the exitorioe.

The operation of this apparatus shouldbe ap arent from the abovedescription. The mo ten la is drawn downwardly in the form o a sheet 17from the plastic glass which is practically sus nded around member 7. Asthe glass is rawn away in sheet form, the suspended source iscontinuall7 replenished from the glass flowing down rom the receptacle.The sheet may" be pulled down b any suitable drawing means and vmay bebent into thehorizontal'plane while still somewhat plastic, or maybecarried continuonsly downward in the vertical plane until it issuiciently set to be cut into sections.

A second form of the invention which has several preferred features isillustrated in Figs. 5 to 8, inclusive. AIn this apparatus the inganchoring or supporting means for the sheet source comprises a pair ofsimilar pivoted members 20 and 21, mounted at their upper ends onsuitable pivots or shafts 22 and 23, respectively. Sets of interlockingfingers 24 an 25 pro'ect downwardly from the members 20 an `21 throughthe slot or assage 26 in the glass-containing receptacle 2 T e lingers24 are joined at their lower ends, be-A low the Aslot 2 6, by across-bar 28, whereas the arms 25 are 'oined by a similar parallelcross-bar 29. he molten glass 30 in receptacle 27 flows down throughslot 26 between the interlocking fingers 24 and 25, and 'between andaround the cross-bars 28 and 29, in much the same manner that it flowsthrough and around the anchorin tile 5 in the modification firstdescribed.` at iszto say, the upper edges of the cross bars 28 and 29constitute, in effect, outwardly extendingI ridges or shelves, each ofwhich provides a means Afor accumulating a supply of molten lass'andtemporarily supporting the same fore it flows downward y around the saidcross bars to the sheet source. In the present alpparatus, however, thetwo components of t e supporting member are independently adjustable inseveral ways as will be presently described, whereby the proportions ofthe various glass p may be suitably varied.

At each end the supporting shafts 22 and 23 for the members 20 and 21are carried in j a pair of similar bearing blocks 31 and 32. Onthe endof each of the shafts 20 and 21 is fixed an upwardly extending arm 33,which is held in a normal vertical position between a pair ofcompression spmngs 34 and 35. These springs 34 and 35 abut at theirouter ends against adjlusting screws 36 and 37, respectively, whic arecarried in fixed ears 38 on the supporting block 31 or 32. -In'this waythe member 20 or 21, is normally held in a fixed position, but mayoscillate one .way-

or another against the force of the springs 34 or 35 when unusualstresses are applied tothe downwardly pro'ecting'glass supportrtion ofthe anc oring member. The bloc 31 and 32 are mounted for horizontalsliding movement toward or from one another in a vertically slidablebearing block lio l 39. A screw 40 secured at one end to the block 31 or32, projects through a suitable opening in theblock 39, and a nut 4lmounted .on this screw is carried in a slot or o ening-42 in the bearingblock 39. By suita ly manipulating one or both of the nuts 41, themembers 20 and'2l may be properly adjusted toward or from one another,or may be properly centered within the passage 26 in receptacle 27. Thesupporting block 39 is vertically-slidable on guides 43 of a fixedsupporting bracket 44 mounted in any suitable manner at the outer sideof the machine. A screw 45 fixed to the block 39 projects up- .influenceof the coolers 56, of any a I mass being drawn 8, the Hoor of t wardlthrou h 'an o ningv in the upper cross h1emberg46 of biiilzket 44. Apair of nuts 47 and 48 mounted on screw 45 and placed at the oppositesides of cross member 46 will support and hold the block 39 in fixedposition, but will allow the block to be adjusted vertically as desired.It will be noted that by means of the mechanism just described, the lasssupporting or anchoring members may adjusted vertically or horizontallyas a unit, the two components may be adjusted toward and from oneanother to vary the size and direction of lthe glass passages therein,and also the members are automatically yieldable to compensate forunusual drawing strains.

As shown more articularly in Figs; 5 and e rece tacle 27 for the moltenglass adjacent t e assage 26 is formed b a pair ofupward y slopingbottom mem ers 49 and 50. These members deliver the molten glass to theslot 26 in rather shallow streams 51 and 52, and also allow the glass tocool down to the proper state of lastic viscosity, for Howing throughand ing drawn downwardly from the-anchoring members 20 and 21.l It willbe noted that the side walls of receptacle 27 conver inwardl at 53 tothe foot of the upward y sloping bottom members 49 and 50. In this Waythe streams of glass flowing toward the slot are first graduallynarrowed and then become gradually shallower as they appreach the slot.the coolin of the Huid glass and delivering it to the raw-off slotin theproper plastic condition.

At either side of the source are heating chambers 54, which direct theirheat against the streams of glass Howing from the edges of the passage26, and around the exterior of the cross-bars 28 and 29. This outerglass is thus maintained in a Huid and free Howing condition to avoidthe formation of surface blemishes. As this surface glass Hows downtoward the meniscus or sheet source 55, below the bars 28 and 29, itcomes under the proved form2 and is set to such a degree of p asticitythat 1t may be drawn smoothly into the surfaces of the sheet 57.

If unusual stresses occur in the glass into sheet form, the -bars 28 and29 will yield somewhat toward one another against the springs 35, but asthis stress is relieved the springs will again tend to spread the barsand compensate forth@ lessening tension. In this way the drawingstresses and the resistance offered by the plastic mass are maintainedin a state of comparative equilibrium, and a more Veven and uniformsheet is produced.

Claims:

l. The method of forming continuous sheet glass consisting in Howing aplurality of This all aids in expediting of pivoted .passages for themolten glass, each member being joined at their lower ends separatedstreams of molten glass, of less width but greater thickness than thesheet, downwardl in contact with faces, also owin apair of streams ofmolten glass downwarcy around the separated streams, and uniting all ofsaid streams to form a source from which the glass sheet is drawn.

2. In an a paratus for drawing sheet glass a container or a sup ly ofmolten lass, an a honey-combed member around an through vflhich moltenglass flows from the supp y, t e sheet form.

3. In an ap aratus for drawing sheet glass, a container or a supply ofmolten glass, and a pair of interlockin .members forming a series ofinterior am? exterior vpassages through which the glass Hows from thesupply, and from which it is drawn awa 1n sheet form, the members beingadjustab e'to vary the size of the interior passa es.

4. In an ap aratus for drawing s eet glass, a receptacle or the moltenglass, having an elongated passage in its bottom, a honeycombed memberpositioned in the passage around and through which the glass Hows, andis drawn away from the lower end in sheet form, and means for heatingthe glass as it Hows around the member.

5. In an ap aratus for drawing sheet glass, a receptacle or the moltenglass, having an elongated orifice in its bottom, and a pair ofinterlocking members positloned in the orifice, and formin a series ofinterior and exterior passages Hor the molten glass, the members beingadjustable to vary the size of the interior passages.

6. In an ap aratus for drawing sheet glass, a receptacle or the moltenglass, having an elongated orifice in its bottom, and a air membershavin interlocliing fingers projecting downward y through the orificeand forming a series of interior and exterior passages for the moltenglass, and means for holding the members under yielding tension so thatthe capacity of the glass passages will vary in accordance with thedrawing stress under which the sheet is drawn away from the lower endsof the members.

7. In an ap aratus for drawingy sheet glass, a receptacle or the moltenglass, having an elongated orifice in its bottom, and a pair of pivotedmembers having interlocking lingers projecting downwardly through theorifice and forming a series of interior and exterior by a continuouscross-bar, the glass being drawn away 'in sheet'form from below thispair of bars.

8. In an apparatus for drawing sheet glass', a receptacle for the moltenglass, having an elongated orifice in its bottom, and a pair glass beingdrawn from the member 1nA supportingsurthe fingers of fingers `projectinoriiceland formin fingers, o

of pivoted members having interlocking g downwardly through'the a seriesof interior and passages or the molten eglass, the each member beingjoin at their lower ends by a continuous cross-bar, the lass being drawnaway in sheet form from low this pair of bars, and means for holding themembers under yielding tension so that the ca acity of the lass passageswill vary in accor ance with t e drawing stress under which the sheet isdrawn away from the lower ends of the members.

9. The methodvof producing sheet glass which nsists in flowing three searated exterior 2 streams of molten glass from a sing e body l through adischarge passage(i in .forming right and left exposed supply bo ies ofglass from the two outer streams beneath the assage, and in causin theglass of the centr stream and the ove ow from the supply bodies to mergeat a point beneath the said bodies and to advance therefrom in sheetformation.

10. The method of producing vrsheet glass which consists in formingthree separated flows ofmolten glass from a single body within` adischarge orifice, in forming right and left exposed supply bodies fromtwo of the said `flows of lglass beneaththe orifice, and in cansin theglass of the central ow and the over ow' from the supply bodies to mergeat a point beneath 'the supply bodies and to advance therefrom in sheetformation by applying drawing forcel to the glass'along its mer lngzone.

11. e method lof producing sheet'glass which consists in forming threevseparated flows of molten glass from a. single body within a. dischargeorifice, in forming right and leftexposed supply bodies from two of thesaid vflows of glass beneath the said orifice, and in causing the glassof the central flow and the overfiow from the supply bodies to mer' at apoint beneath the said supply .bodies and to advance from said point insheet formation by applying drawing force to the glass along its mergingzone and during drawing ap lying fluency increasing heat to the glassorming the supply bodies.

12. The method of producing sheet glass which consists in flowing threese arated streams of molten glass from, a sing e body through adischarge passage, in forming right and leftexposed supply bodies ofglass from two of the said streams beneath the passage,

and in causin the glass of the central stream and the over ow rom thesupply 'bodies to merge at a point beneath the said supply bodies andto'advance from' said point in sheet formation by applying drawing forceto the glass along its merging zone and durving drawing applying fiuencyincreasing heat forming the supply bodies while tothe glass from theouter surfaces .causing a loss of heat of the glass in the merging zone.

neaaeaa vto a vance therefrom in sheet ormation, and

during the sheet forming, heating the sur- TISA face layers of thesupply bodies prior to their advance into the mer ng zone.

14. The method o producing sheet glass which consists in forming threead`aoent, supported, s treamflows of molten glass vfrom a single bodywithin av discharge orifice, in forming right and left exposed supplybodies i from two of the said flows beneath the orifice,

in causing the glass of the central iow and the overflow from the supplybodies to merge at a point beneath the said bodies and to advance fromsaid point in sheet formation, and during the sheet forming, heatin thesurface layers of the supply bodies prior to their advance into themerging zone, while cooling,

opposite surface layers of the sheet below its oint of formation.

1 The method ofobtaining a sheet from a body of molten lass-which isdischarging downward throng lan orifice, which consists 1n supplyingglass of plastic'nature to the orifice to form a discharging body, inproviding retardin means for building up surface supplying odies and toreduce the discharging velocity in and below the orifice, in surroundingthe discharging portion of the body which is beneath the orifice with aheating atmosphere to induce iluency'in its' externa portion, and -inproducing a sheet of glass by accelerating 'the downward movement of thedischarging glass beneath' the point of heat application thereto.

16. The process of drawing a sheet of glass which consists in convergingand merging three descending streams of plastic glass into a sheetsupplying source, in checking the descent of two of the streamsabove thecommon merging point to build up right and left supply bodies adjacentsaid point, in increasing the fluidity of said bodies by localsuperheating, and in drawing a sheet of glass frOm the source. l

17. The method of making sheet glass,4

down assenso pass means for flowing mo ten g ass onto thel up-v peredgees of the members, the glass flowing tween the members, and alsodown the outer sides thereof, the three streams uniting below themembers and being drawn away in sheet form, the members being pr videdon their outer faces with means for retaining a supply body of glass ineach outer vstream adjacent the point where the streams merge.

19. In an apparatus for forming continuous sheet gla, a pair of similardirecting members arranged adjacent one another so as to provide an openpassa therebetween, means for flowing molten g ass onto the upper edgesof the members, the glass flowing down between the members, and alsodown the outer sides thereof, the three streams unitthe outer sidesthereof, the three streams uniting below the members and being drawnaway in sheet form, the members bein provided on their outer faces withmeans or retaining a supply body of glass in each outer stream adjacentthe point where the streams merge, and means for applying heat to theseglass supplies.

' 21. In an apparatus for forming continuous sheet glass, a pair ofsimilar directing members arranged adjacent one another so as to providean open passage therebetween, means for flowing molten glass onto theupper edves of the members, the glass owing down between the members,and also down the outer sides thereof, the three streams unitin belowthe members and being drawn away 1n sheet form, the members beingprovided on their outer faces with glass retaining led es, and means forheating the glass on the edges. v

22.' In an apparatus for forming continuous sheet glass, a air ofdirecting members between and aroun which molten glass iows to form asheet sour at the lower ends of the members, and means for supportingthe v 23. In an apparatus for forming continuous sheet lass, a air ofdirecting members between an aroun which molten glass Hows to form asheet source at the lower ends ofthe members, and-means for yieldablysupporting the members.

24. n an apparatus for forming continuous sheet glass, a pair ofdirecting members between which molten glass flows to a sheet and meansfor holding these members yieldably against the stream of flowing glass.

25. In an apparatus for forming continuous sheet lass,.a air ofdirecting members between w ich mo ten glass flows to a sheet source,suspended from the lower ends of the members, and means for holding themembers yieldably against the flowing glass stream.

26. In an apparatusfor. forming continuous sheet glass, a receptacle formolten lass having an orifice in its bottom, a pair o directin membersextending down through the orifice, the molten glass flowing down inthree separated streams, one between the members, and one between eachmember and the adjacent side of the orifice, and means for mounting themembers whereby ,they may yield toward or from one another to vary theproportionate volumes of the side and central streams.

27. In a glass drawing apparatus, the combination of vertically disposedconforming means down opposite sides of which glass is permitted to flowin film formation, and means for yieldably supporting said conformingmeans in position.

28. In a lass drawin apparatus, the com bination og vertically 'sposedconforming means down opposite sides of which glass is rmitted to iow infilm formation, and ad justable yielding supporting means for saidconforming means. v

29. In a lass drawing a paratus, the combination o a vertically isposedtwo-part conforming member, and means for rmit- -ting'relativeyieldability between sai parts.

30. In a glass drawing apparatus, the combination of a two-partvertically disposed conforming means, said parts cooperating to form acentral passage, means for delivering glass to the outer sides of saidconforming means and to the interior of the passage, and means wherebyone of saidparts may be adjusted with res ct to its, cooperating part.

Signed at Ci arleston in the county of Kanawha, and State of West.Virginia, this 5th day of October 1922.

- ENCH T. FERNGREN.

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